Cathode structure



} Nov.2,1948. HMWLL 2,452,786

CATHODE STRUCTURE Filed Feb. 18, 1946 //v yew ran.

HARRY T. O'ENEILL ATTORNEY Patented Nov. 2, 1948 CATHODE STRUCTURE Harry'1. ONeill, Taunton, Mass, assignor to the United States of America asrepresented by the Secretary of War Application February 18, 1946,Serial No. 648,544

2 Claims.

This invention relates'to electronic devices, and, more particularly toan electronic Vacuum tube of the resnatron type for generatingultra-high frequency power.

Because of the high power output of the resnatron type tube, and thehigh temperatures developed within the device and between the electrodesthereof, fluid cooling means are customarily associated with the device,particularly with the cathode unit, with the screen or accel cratinggrid, and with the anode. It is common practice to incorporate aflexible, generally cylindrical, bellows in the cooling arrangement forthe cathode unit. the bellows being of a metallic material, and solderedat a lower open end portion to a suitable conforming-shaped portion ofthe cathode unit, for example, an upper ring-like metallic portionthereof on which one end of the cathode filaments are terminated.Failure of the soldered seal tween the bel ows and the oathode unitresults in the destruction of the vacuum within the tube through leakageof the cooling fluid. During the operation of the resnatron, a largeamount of heat must be carried through the cathode portion to which thebellows is connected, and to the cooling fluid. When a recirculatingwater system is used for cooling. the water may run hot enough to allowthe cathode ring-l ke up er portion to reach the melting point of the soder in the region where the bellows is attached, thus loosenin it andfilling the vacuum system of the tube with water.

An object of the invention is to improve the structure of a resnatron tominimize the possibility of failure of the vacuum therein because ofleake ge of cooling fluid.

A feature of the invention com rises securing the referred-to bellows tothe cathode unit of a resnatron, with a clearance s ace provided betweena portion of the bellows and the cathode unit to increase the heatradiating area of the cathode unit.

A more complete understanding of the invention will be obtained from thedeta led de crin tion that follows, taken in conjunction with theshowings of the appended drawing. wherein:

Fig. 1 shows a cross-sectional view of the oathode unit of a resnatronincorporating this invention; and

Fig. 2 in a sectional view of the device of Fig. 1 taken along the line22 thereof.

With reference to the drawing, there is shown a cathode unit ll? of aresnatron, including a cathode comprising a plurality of cathodefilamerit wires I 2, spaced from each other but arranged to form agenerally cylindrical, cage-like structure having a pair of metallicmembers or rings l4, H5 at their upper and lower ends to which the endsof the individual wires l2 may be $01- dered. The members l4, it havecentral passages i8, 29, respectively, for suitable conduits or pipes(not shown) for cooling fluid, for example, water, as already well knownin the art. A generally cylindrical, flexible bellows or sylphon 22 thatmay form a part of the cooling means for the resnatron has a lowerportion 24 that extends into the passage l8 and is fastened to thepassageway wall, for example, with solder. The upper portion 26 of thering I4 is recessed or cut away to provide an annular recess or space 28between the bellows portion 24 and the ring Hi. The provision of therecess 28 adds the heat radiating surface of the unit. The cooling fluidthat flows inside the ring and the bellows reduces the temperature ofthe solder seal which the bellows forms with the ring I4. Thepossibility that the vacuum of the resnatron tube will be disturbed as aresult of leakage of cooling fluid through the upper cathode ringbellowsseal is markedly minimized.

Although the invention has been disclosed with reference to a specificconfiguration, obviously it is not limited thereto, but is to beconsidered of a scope within the purview of the prior art and theappended claims.

What is claimed is:

1. An electronic device comprising a cathode unit including a pluralityof filament wires spaced from one another and mounted in a generallycylin rical configuration, vertically spaced centrally-aperturedmetallic cooling members to which the upper and lower ends of said wiresare respectively secured and a bellows having and end portion extendinginto the central aperture of one of the upper said metallic members andsecured to the aperture thereof, said last-mentioned metallic memberproviding an annular space surrounding said end portion, said bellowsbeing open to receive circulating water passing through the centralapertures of said metallic members.

2. An electronic device comprising a cathode unit including a pluralityof filament wires, a centrally-apertured metallic member providing asupport for the upper end of said filament wires, and a bellows forminga portion of a cooling system for the cathode unit, said bellows havingan end portion extending into the aperture of said metallic member andsecured thereto, said member being counter-sunk around said end portionto provide an annular space therearound,

3 bellow being open to receive circulating water passing through thecentral apertures of said metallic members.

HARRY T. ONEILL.

CITED The following references are of record in the file of this patent:

Number Certificate of Correction Patent No. 2,452,786 November 2, 1948 IHARRYIT. ONEILL It is hereby certified that errors appear in the printedspecification of the above numbered patent requiring correction asfollows:

Column 2, line 38, for the words having and read having an; line 40,strike out the upper and insert the same after aperture of in line 39line 49, for end read ends; and that the said Letters Patent should beread with these corrections therein that the same may conform to therecord of the case in the Patent Oflice.

Signed and sealed this 17th day of January, A. D. 1950.

THOMAS F. MURPHY,

Assistant C'ommz'ssz'oner of Patents.

